Tempo enhancement device

ABSTRACT

An electromechanical apparatus accompanies rhythmic human movement with music of appropriate tempo. This is accomplished by monitoring the activity with a transducer attached to a supporting structure, which will move in response to shifts in human weight. These peaks are counted and the measured count is used to control the relative volumes of a multiplicity of differently paced musical tracks.

Elmte States Paten 11 1 1111 3,865,001

Hershey Feb. 11, 1975 [54] TEMPO ENHANCEMENT DEVICE 3,539,701 11/1970Mlldc 84/].28 3,634,596 1 1972 R 1 84 1.28 [761 lnvemorlRbmL-Herhey1255NeW 3,704,339 11/1972 ..s4/1.24 HamRShire NW. 3,705,94812/1972 Tomisawa... 84/].24 Washmgton, DC 20036 3,749,810 7/1973 Dow84/124 22 Filed: May 10, 1973 Appl. N0.: 358,956

Related U.S. Application Data Continuation-in-part of Ser. No. 174,464,Aug. 24, 1971, abandoned.

References Cited UNITED STATES PATENTS 12/1969 Rupert 84/128 X PrimaryE.\'umir1er-Richard B. Wilkinson Assistant E.\'z1n11'nerStanley J.Witkowski [57] ABSTRACT 1 Claim, 4 Drawing Figures PULSE TRANSDUCER"'ZAPUHEF? SHAPER D|G|TALTO-ANALOG NETWORK TAPE AMPLIFIER SPEAKER SLOWSLOW (SLOW TRACK CHANNEL CHANNEL) DIFFERENTIAL H AMPLIFIER CIRCUIT TAPEAMPLIFIER SPEAKER FAST FAST (FAST TRAcR CHANNEL CHANNEL) Pmmmrwn a I3.865.001

' sum 10F 4 PIC-11 PAIENTED FEB] 1 I975 SHEET l 0F 4 ok ztoa TEMPOENHANCEMENT DEVICE This application is a continuation-in-part ofapplication Ser. No. l74,464, filed Aug. 24, l97l, and now abaondoned.

BACKGROUND OF THE INVENTION This invention relates to an apparatus forautomatically sensing the tempo of some form of human activity andenchancing its rhythm by actuating appropriately paced musicalaccompaniment.

In various situations it often is desirable to enhance the tempo of somerhythmic activity such as dancing, gymnastics, trampoline acrobatics, orexercising. Accompanying sound adds another dimension to the activity,increasing the awareness of its rhythm for the participants andspectators. Such accompaniment could previously be obtained only throughmanual control of the music. With this invention the control isautomatic. By eliminating the manual operator labor costs are saved,privacy is increased, and the activity is more directly linked to itsaccompaniment.

SUMMARY OF THE INVENTION Each type of rhythmic human activity generatessome movement of the supporting structure which can be instrumented byan appropriate form of transducer, producing a time-varying voltage. Thetype of activity dictates the most efficient transducer for monitoring.Typical transducers that may be used in various embodiments of thisinvention include accelerometers, spring-loaded contacts, strain gauges,and conducting rubber rheostats. For instance in monitoring dancing orgymnastics a vibrational transducer in contact with the floor or matsuch as an accelerometer could be used.

This invention comprises a unique electromechanical network whichresponds to the repetition rate of the motion. This is transformed intothe repetition rate of a voltage through the use of a transducer. Therepetition rate of the motion is counted, and this count is used toselect the relative volume for each of a multiplicity of differentlypaced music tracks.

An embodiment of the invention will now be described with reference tothe appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an external view of theapparatus, showing how it may be used in conjunction with a home stereotape recorder system.

FIG. 2 is a schematic diagram showing the electromechanical networkutilized in the embodiment.

FIG. 3 is a schematic diagram of the detail of the digital-to-analognetwork.

FIG. 4 is a circuit diagram showing the detail of the differentialamplifier circuit.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. I the transducer 1, inthis case an accelerometer is shown monitoring an activity. Theelectrical signal from the transducer is processed by the circuitry tobe described, which is a modification of a home stereo amplifier unit 2.The input to the stereo amplifier consists of a home stereo taperecorder 3 playing a special stereo tape 4, whose first channel consistsof slow music and whose second channel consists of appropriatelysyncopated fast music. The stereo amplifier unit 2 sets the relativevolume of the music from the two tape tracks. A slow tempo in themonitored activity causes the amplifier, 2 to make the slow track loudercompared to the fast track. Similarly for a fast tempo activity thesound of the faster musical background predominates. The music from thetwo tracks, with their relative volumes thus regulated, issues forthfrom the two speakers 5 and 6, respectively.

Referring to FIG. 2, the schematic of the electromechanical network isshown. The signal produced by the transducer 1 is a time-varying voltagewith its peaks corresponding to the peaks of the movement beingmonitored. These peaks occur when the shifting body weight causes thesupporting structure to make excursions above and below its equilibriumposition. The signal from the transducer is amplified by a standardelectronic amplifier circuit 8. This amplified signal is input to thepulse shaper circuit 9, which forms a pulse from each peak of thesignal. These pulses control a digitalto-analog network circuit 10 whichgenerates an analog voltage proportional to the time between pulses. Theoutput of the digital-to-analog network 10 forms the input to thedifferential amplifier circuit 11. The left and right channels of a homestereo amplifier constitute the slow and fast channels 12 and 13,respectively. The differential amplifier circuit 11 uses this voltagefrom the digital-to-analog network, proportional to the period of pulserepetition to control the slow (left) channel amplifier 12 and the fast(right) channel amplifier 13 of the home stereo amplifier. This is doneby biasing a stage of amplification of each channel with volt age fromdifferential amplifier, adjusting the balance of volume between thesetwo channels. If the voltage from the digital-to-analog network 10 isequal to a preset level corresponding to an intermediate speed pulserate reference, the sounds will be balanced in both channels. If thepulse rate is higher than the preset level, the volume will beconcentrated in the fast channel; if less, it will be concentrated inthe slow channel. The right and left channels of the tape recorderoutput 14 and 15, which were derived from the special stereo tape 4, arethen amplified by the right and left channel amplifiers 12 and 13 of thehome stereo amplifier. Since the balance of the volume between theseamplifiers l2 and 13 has been adjusted on the basis of the period ofpulse repetition, the amplification of the fast track channel will begreater if the pulse repetition rate is faster than the reference rateand the amplification of the slow track channel will be greater if thepulse repetition rate is slower than the reference rate. The audiosignals from the amplified musical tracks then go the speakers 5 and 6.If the sensed motion is slow in tempo then the sound from the slowchannel speaker 5 will be louder and predominate, and if the sensedmotion is fast in tempo then the sound from the fast channel speaker 6will be louder and predominate.

The detail of the digital-to-analog network is shown in FIG. 3. Thepurpose of this network is to determine the time period betweensuccessive pulses and put out an analog voltage proportional to thisperiod, and thus inversely proportional to the pulse repetition rate.Incident pulses from the pulse shaper reset all the elements of thedigital-to-analog network and direct the set of logic 19 to permit atrain of pulses from the clock 18 to be counted in the binary counter20. When the next incident pulse occurs, the contents of the binarycounter are transferred to a storage register where they are convertedto analog form by the digital-to-analog mined by the count accumulatedby the counter during I the period. The process of counting can,therefore, continue for the next time interval, the value of the countfor the previous interval being stored in the register. When the pulseoccurs, the second counter number will be read into the register 21,erasing the existing contents and converting it to analog via thedigital-toanalog converter 22. The output of the digital-toanalogconverter 22 is a voltage proportional to the period. This voltage isthen put through the low pass filter 23 before being fed to thedifferential amplifier circuit.

FIG. 4 shows the differential amplifier circuit consisting of asubtractor amplifier and an inverter. The subtractor amplifier portionconsists of operational amplifier 24, associated resistors 25 and 26, dcbias voltage source 27, and potentiometer 28. The inverter portionconsists of operational amplifier 29 and associated resistors 30 and 31.The filtered analog signal from the digital-to-analog network iscompared to the preset reference voltage level of the potentiometer 28,which establishes the balance position for the period of repetition.This reference voltage corresponds to the voltage that would come fromthe analog-to-digital network for an intermediate speed pulse repetitionrate. The subtractor amplifier produces a voltage proportional to thedifference between the reference voltage and the analog input. Thisvoltage determines the magnitude of voltage biasing a stage ofamplification of the fast channel of the stereo amplifier and thuscontrols its gain. To obtain the algebraic negative of the outputvoltage from the subtractor amplifier it is fed to an inverter,consisting of operational amplifier 29 and resistors 30 and 31. Thisresults in a voltage equal to the difference between the analog inputand the reference voltage which goes to the slow channel of the stereoamplifier. If the analog input is larger in absolute value than thereference voltage, the voltage to the fast channel amplifier will benegative and the voltage to the slow channel amplifier will be positive.Both voltages will be proportional to the difference between the analoginput and the reference. Conversely if the analog input is less than thereference voltage the voltage to the fast channel amplifier will bepositive and the voltage to the slow channel amplifier will be negative.

To obtain more than two speeds of background music additional channelsmay be used with a device for selecting among the channels. If enoughadditional channels are used an almost continuous range of backgroundmusic speeds can be obtained.

All that has been said with reference to a tape music reporductionsystem could also be accomplished with a disc or some other form ofmusic reproduction system.

It is also possible to augment the sound with a light display of variouscolors corresponding to various pulse repetition rates. This can beaccomplished by having bulbs of various colors light in response tovarious levels of voltage measured at the output of the low'pass filter23. One means of switching the bulbs is with a control circuit such asdescribed in U.S. Pat. No. 3,480,912 to S. D. Speeth and P. C. Norem.Further rhythm accompaniment can be obtained by triggering a rhythminstrument with the peak values of the electrical signal from thetransducer. Other modifications will be obvi-. ous to those skilled inart.

The invention is not limited to the exemplary construction shown above,but may be made in various ways within the scope of the followingclaims.

What is claimed is:

1. In a device for changing the relative volumes of at least two sourcesof differently paced musical selections in response to the tempo ofmovement of a supporting structure caused by shifts of human bodyweight;

a. an electromechanical transducer for sensing said structural movementand producing a variable voltage in response thereto whose peakscorrespond to the excursions of the structure in response to said shiftsin human body weight;

b. an amplifier for amplifying said voltage;

c. a pulse shaper to form pulses from said amplified voltage;

d. a digital-to-analog network to produce from said pulses an analogvoltage proportional to their period of repetition;

e. a differential amplifier circuit to produce plural output voltagesfrom said analog voltage proportional to the period of repetition;

f. a multichannel amplifier, a stage of amplification in each of whosechannels is biased by one of said output voltages, thus producingdiffering levels of amplification;

g. at least two musical tracks having differing rhythm speeds,prerecorded on different channels of a recording medium, which areamplified to differing degrees by said multichannel amplifier; and h. atleast two speakers to produce sound from said prerecorded musicaltracks.

1. In a device for changing the relative volumes of at least two sourcesof differently paced musical selections in response to the tempo ofmovement of a supporting structure caused by shifts of human bodyweight; a. an electromechanical transducer for sensing said structuralmovement and producing a variable voltage in response thereto whosepeaks correspond to the excursions of the structure in response to saidshifts in human body weight; b. an amplifier for amplifying saidvoltage; c. a pulse shaPer to form pulses from said amplified voltage;d. a digital-to-analog network to produce from said pulses an analogvoltage proportional to their period of repetition; e. a differentialamplifier circuit to produce plural output voltages from said analogvoltage proportional to the period of repetition; f. a multichannelamplifier, a stage of amplification in each of whose channels is biasedby one of said output voltages, thus producing differing levels ofamplification; g. at least two musical tracks having differing rhythmspeeds, prerecorded on different channels of a recording medium, whichare amplified to differing degrees by said multichannel amplifier; andh. at least two speakers to produce sound from said prerecorded musicaltracks.